Direct detection and spectral characterization of extra-solar planets is one of the most exciting but also one of the most challenging areas in modern astronomy. The challenge consists in the very large contrast between the host star and the planet, larger than 12.5 magnitudes at very small angular separations, typically inside the seeing halo. The whole design of a “Planet Finder” instrument is therefore optimized towards reaching the highest contrast in a limited field of view and at short distances from the central star. Both evolved and young planetary systems can be detected, respectively through their reflected light and through the intrinsic planet emission. We present the science objectives, conceptual design, and expected performance of the SPHERE instrument. LAOG, CNRS/Universite J. Fourier, B.P. 53, Grenoble, France Max Planck Institute for Astronomie, Konigsthul 17, Heidelberg, Germany LAM, CNRS/Universite de Provence, B.P. 8, Marseille, France Observatoire de Geneve, 51 ch. des Maillettes, Sauverny, Switzerland Laboratoire H. Fizeau, UNS/CNRS/OCA, Nice, France Osservatorio Astronomico di Padova, INAF, Vicolo dellOsservatorio 5, Padova, Italy LESIA, CNRS/Observatoire de Paris, 5 place J. Janssen, Meudon, France European Southern Observatory, Karl-Schwarzschild-Strasse 2, Garching, Germany ONERA, B.P. 72, Chatillon, France NOVA/ASTRON, Oude Hoogeveensedijk 4, Dwingeloo, The Netherlands Institute of Astronomy, ETH, Zurich, Switzerland Universitat van Amsterdam, Kruislaan 403, Amsterdam, The Netherlands